5) \( 12.9 \cdot-0.8= \)

Did you know that multiplying positive and negative numbers follows a simple rule? The product of a positive number and a negative number is always negative! So, when you calculate \( 12.9 \cdot -0.8 \), you can first ignore the signs and multiply 12.9 by 0.8 to get 10.32, and then add the negative sign to get -10.32! If you want a quick tip: when multiplying decimals, count the total number of digits to the right of the decimal points in the numbers you’re multiplying. For \( 12.9 \) and \( -0.8 \), there’s one digit after the decimal in \( 0.8 \) and one in \( 12.9 \), so your final answer, -10.32, will have two digits after the decimal!